Adaptive quadrature-polybinary detection in super-Nyquist WDM systems.

We propose an adaptive detection technique in super-Nyquist wavelength-division-multiplexed (WDM) polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) systems, where a QPSK signal is digitally converted to a quadrature n-level polybinary signal followed by a MLSE detector at the receiver, and study the performance of quadrature-duobinary and quadrature four-level polybinary signals using this detection technique. We change the level of the quadrature-polybinary modulation at the coherent receiver according to the channel spacing of a super-Nyquist system. Numerical studies show that the best performance can be achieved by choosing different modulation levels at the receiver in adaption to the channel spacing. In the experiment, we demonstrate the transmission of 3-channel 112-Gbit/s PDM-QPSK signals at a 20-GHz channel spacing, which is detected as a quadrature four-level polybinary signal, with performance comparable to PDM 16-ary quadrature-amplitude modulation (16QAM) at the same bit rate.

[1]  Chongjin Xie,et al.  Quadrature duobinary modulation and detection , 2015, 2015 Optical Fiber Communications Conference and Exhibition (OFC).

[2]  Jianjun Yu,et al.  400 G Transmission of Super-Nyquist-Filtered Signal Based on Single-Carrier 110-GBaud PDM QPSK With 100-GHz Grid , 2014, Journal of Lightwave Technology.

[3]  A. Lender.  Correlative Digital Communication Techniques , 1964 .

[4]  Jie Zhang,et al.  Comparison of Advanced Detection Techniques for QPSK Signals in Super-Nyquist WDM Systems , 2015, IEEE Photonics Technology Letters.

[5]  G. David Forney,et al.  Maximum-likelihood sequence estimation of digital sequences in the presence of intersymbol interference , 1972, IEEE Trans. Inf. Theory.

[6]  Jie Zhang,et al.  Advanced detection of super-Nyquist WDM QPSK signals with 5-bit/s/Hz spectral efficiency , 2015, 2015 Optical Fiber Communications Conference and Exhibition (OFC).

[7]  Junwen Zhang,et al.  Transmission of 8 × 480-Gb/s super-Nyquist-filtering 9-QAM-like signal at 100 GHz-grid over 5000-km SMF-28 and twenty-five 100 GHz-grid ROADMs. , 2013, Optics express.

[8]  J. Conradi,et al.  Multilevel signaling for increasing the reach of 10 Gb/s lightwave systems , 1999 .

[9]  Peter J. Winzer,et al.  Digital Signal Processing Techniques Enabling Multi-Tb\/s Superchannel Transmission: An overview of recent advances in DSP-enabled superchannels , 2014, IEEE Signal Processing Magazine.

[10]  Yi Cai,et al.  Transmission of 96 $\,\times\,$100-Gb/s Bandwidth-Constrained PDM-RZ-QPSK Channels With 300% Spectral Efficiency Over 10610 km and 400% Spectral Efficiency Over 4370 km , 2011, Journal of Lightwave Technology.

[11]  Gregory Raybon,et al.  Digital PLL based frequency offset compensation and carrier phase estimation for 16-QAM coherent optical communication systems , 2012 .

[12]  Zhenning Tao,et al.  Spectrally Efficient Quadrature Duobinary Coherent Systems With Symbol-Rate Digital Signal Processing , 2011, Journal of Lightwave Technology.

[13]  A. Haghighat,et al.  Performance of A 3 MCNP™ for Calculation of 3-D Neutron Flux Distribution in a BWR Core Shroud , 2001 .

[14]  Jianjun Yu,et al.  Multi-Modulus Blind Equalizations for Coherent Quadrature Duobinary Spectrum Shaped PM-QPSK Digital Signal Processing , 2013, Journal of Lightwave Technology.

[15]  I Tafur Monroy,et al.  Five-level polybinary signaling for 10 Gbps data transmission systems. , 2013, Optics express.